Can I control WHO my data is shared with?

Yes, but not directly.

Unfortunately, it's not practical for us to provide you with very fine-grained control over who your data is and is not shared with. Businesses today operate as networks of collaborating service providers, meaning that when we have good reason to share your data with others, we simply need to do so to provide you with the service you're asking for. This means that if you withdrew permission for us to share your data (or especially if you tried to say "Don't share my data with anyone please.") we wouldn't be able to provide you with our products and services.

You do have INDIRECT control though. We can only ever share data that we have, and you have a lot of control over that by simply not answering the questions we ask or not granting your permission for various things when we ask for it. We can also only share data we have a NEED to share, so if the need is not there, we won't share it.